Backhoe sloppy backhoe

[Cade]

My L2650 is 4 wheel drive w/ the GST. I also have a Kubota BL4590 backhoe. I realize that because the backhoe is PTO driven it will not be as smooth, however it seems to be pretty jerky and I have to move the control levers extreemly slow. My RPM are relatively low when I use the backhoe 1500-2200 depending on what I'm doing. I originally thought that the pins that the hoe rotates on bearing or bushings in but they are just a pins that get greased. The cyslinders for the outriggers also seem to constantly leak. I heard that is a common problem and not to worry. Anyone have similar issues and or recommendations?

Thanks in advance

 

[Taiser]

I thought mine was jerky until I got a little more light handed, now it works fine. I also noticed that when I crank up the RPM's you can feather the controls a bit better. I still can't go WOT yet (only 9 hours on machine) but it seems the more power going to the pump the smoother I can control it. I don't think a PTO pump would make any difference in the unit being more jerky, but I could be wrong.

 

[john_bud]

Couple questions.

Is the fluid full up to the top? Are you measuring with the cylinders full in, full out or in the middle?

Have you changed the fluid filter(s)? Cleaned the inlet screen (if it has one)? Changed the fluid ? (May have water in it) Is the fluid a mulitvis like SUDT or a straight vis like UDT? In cold weather, the fluid can pump real hard and give jerky operation until it warms up (operating temperature for hydraulic fluids is in the 120-160F range). You may want to switch to a multivis or a thiner fluid for winter.

Leaking cylinders can sometimes be slowed (or stopped) by tightening the end caps. Have you tried that? May need a pin wrench to do it, not sure what the cyl looks like. The lines may also be loose, check them too.

You may want to run the engine up so that the PTO is spinning at 400 rpm or so. Fast enough to run well, but not scary fast as you are learning. Lower than that and you may not have enough flow for smooth operations.

Last bit of advice is just to practice more. A smooth hand will give smooth operations with the hoe, but that takes time!

Enjoy,
jb

 

[Cade]

john bud,

Thanks for the response. I will look into your suggestions and see if its the operator or the tool. Actually I'm not sure if it is the operator, it just seems so sensative and I have to really move the controls so slow or it will be jerky/sloppy.

thanks again!

 

[john_bud]

If all the levels are correct, the filters fresh and the screens clean, then you may have to do some think'n and digg'n into the mechanism of the controls.

I didn't ask, when does it seem jerky? Side to side operations? Raising the boom? Extending the dipper stick? Lowering the boom? Curling the dipper?, Curl/extend the bucket? All?


If you throttle down to 1200 rpm, and with the boom up do a full extension of the dipper stick straight up with the control pegged, is it jerky or smooth? Same thing going down? Repeat with the bucket full.
Then raise the dipper fully, shut off the PTO, repeat the lowering test. Jerky or smooth?

Dipper stick full out, boom level with the ground. At 1200 rpm, raise then lower the boom with the control pegged. Jerky or smooth? Raise the boom again, shut off the PTO and lower.

With the dipper stick extended and the boom level how much play is there in the pins/bushings when you manually wiggle it?

Do those tests and let us know what you find out.

jb

 

[Cade]

john bud,

I noticed it mostly from side to side action. I need to also check the chain tension. I just took the hoe off about 2 hours ago for snow removal tomorrow. I will let you know what happens when I reattach it and try your sugesstions out.

 

[tawilson]

I think it's the nature of the beast. Give it time, and try to use another function when you are swinging. Seems to slow mine down.

 

[jfay]

I just rebuilt a Kubota 4530 from the late 80s.

If your outrigger cylinders are leaking out through the packing, buy a rebuild kit (+/- $25) and put in all new seals. That should stop any leaking.

Try moving the backhoe side to side by hand and see if it just slop, maybe tighten the chain and it won't move so much.

Good luck.

J.

 

[john_bud]

How is the swing done on that hoe? Is it one double acting cylinder driving a chain or 2 single acting cylinders? Is there a cushion valve in the path?

I would manually check for loosness and then check for air in the cylinder. You may have a leaky cylinder that is making it spongy.

jb

 

[xyzer]

I know this thread is old but not to many folks are asking questions about the BL4590 on the web. I have a bl4590 I just mounted on a GL4330. I know it could handle a larger one but I have a older John Deere 420c I might hang it on for some other jobs. The 4590 is used and I have been playing with it and have discovered a issue in the main boom valve that will cause it to be....well jerky. If you gently try to raise the main boom it will start to drop and you need to give it more lever to stop the drop. Of course when you do that it will start to raise but faster than you want. Also it seems to be intermintint. it will work properaly sometimes maybe 5% of the time. The valve definatly seems to have a problem. All of the other valves have good sensitivty either direction. I would also like to find a manual if they exist. Are the valves rebuildable? Any suggestions on what the fix is will be appricated.